Fun little puzzle. Took me a solid 90 minutes. It also took me about 30 minutes to figure out how best to do the puzzle since it's a PDF and that's not the easiest medium to edit. I'd recommend an image version, or a better way of allowing people to play. (I suppose I could have printed it? Perhaps suggest as much).
Other comment is -- without giving anything away -- the wording of the final message is quite confusing at first, because of the lack of punctuation. I suggest hiding some full stops (periods) in appropriate places so someone might discover those and figure how to read more clearly.